Prior RFID (radio frequency identification) tags exist that are used to help track various products. RFID tags are typically an assembly including an RFID transponder coupled into a protective housing, and the assembly can then be used for assets management, container safety inspection purposes, fraud prevention, ownership identification or other purposes. One application for such RFID tags, for example, is the use of RFID tags to help track hazardous products, such as liquid propane gas (LPG) stored in metal containers or cylinders.
FIG. 1A (Prior Art) is a diagram of an embodiment 100 including a container or cylinder 102. The container 102 can be, for example, a metal cylinder holding LPG (liquid propane gas) or other hazardous or non-hazardous material. The gas cylinder 102 includes a metal valve flange 108 welded into a central opening at the top of the cylinder 102. As described in more detail below, the metal valve flange 108 can be configured to provide a primary valve opening into which a valve can be inserted and coupled. For example, the opening can be threaded to allow a primary valve to be attached by screwing the valve into place. As also described further below, a second opening can also be provided in the metal valve flange into which a second valve can be inserted and coupled. For example, the second opening can also be threaded and provide a secondary access port into which an emergency pressure relief valve can screwed into place. Such a relief valve is a mandatory regulatory requirement in some geographic regions for certain containers, such as metal cylinders holding LPG in Brazil In addition, as depicted, one or more metal stay plates 106 can also be connected to the gas containing portion of the cylinder 102 and to a metal ring 110. The metal ring 110 can be used, for example, to protect valves coupled to a metal valve flange 108, and the metal ring 110 can be used for picking up or moving the cylinder 102.
FIG. 1B (Prior Art) is a diagram for a metal valve flange 108 for the metal cylinder 102 of FIG. 1A (Prior Art). The metal valve flange 108 includes a primary valve opening 114 and a secondary valve opening 112. The primary valve opening 114 is configured to receive a valve, such as a brass valve, which can be screwed into place. The secondary port opening 112 is also configured to receive a valve, such as a brass pressure relief valve, which can also be screwed into place.
Many gas containers or cylinders, such as those represented in FIGS. 1A-1B, are already in commercial use, and do not have RFID tags or RFID transponders for security and tracking purposes. Further, existing containers or cylinders are being re-used so that many non-tagged containers and cylinders are still being used and will likely continue to be used. As part of the re-use process, a metal identification plate is often used to label or re-label the container/cylinder after mandatory periodic requalification, overhaul and/or retesting of the cylinder has been performed.
FIG. 2A (Prior Art) is a diagram for a metal plate 200, such as a C-shaped metal plate, that can be used to provide labeling information for a cylinder 102 that has been re-qualified. The metal plate 200, for example, can include company information, tare weight of the container, data pertinent to the requalification process performed, date of next inspection and/or any other desired information required by the regulating agency.
FIG. 2B (Prior Art) is a diagram for a metal plate 200 that has been coupled to a valve flange 108, for example, by welding the metal plate 200 to the valve flange 108. As in FIG. 1B (Prior Art), the valve flange 108 can include a primary valve opening 114 and a secondary relief valve port 112, if desired.
As stated above, many gas containers or cylinders, such as those represented in FIGS. 1A-1B, are already in commercial use, and do not have RFID tags or RFID transponders for safety, security and tracking purposes. Determining an effective and secure method for including RFID transponders on these gas cylinders is a difficult problem facing many countries that rely heavily on gas cylinders for energy needs. Further, one problem associated with placing RFID transponders on prior art gas cylinders is that metal structures, such as metal stay plates and protective rings, interfere with RFID communications.